Golf is enjoyed by a wide variety of players—players of different genders and dramatically different ages and/or skill levels. Golf is somewhat unique in the sporting world in that such diverse collections of players can play together in golf events, even in direct competition with one another (e.g., using handicapped scoring, different tee boxes, in team formats, etc.), and still enjoy the golf outing or competition. These factors, together with the increased availability of golf programming on television (e.g., golf tournaments, golf news, golf history, and/or other golf programming) and the rise of well known golf superstars, at least in part, have increased golf's popularity in recent years, both in the United States and across the world.
Golfers at all skill levels seek to improve their performance, lower their golf scores, and reach that next performance “level.” Manufacturers of all types of golf equipment have responded to these demands, and in recent years, the industry has witnessed dramatic changes and improvements in golf equipment. For example, a wide range of different golf ball models now are available, with balls designed to complement specific swing speeds and/or other player characteristics or preferences, e.g., with some balls designed to fly farther and/or straighter; some designed to provide higher or flatter trajectories; some designed to provide more spin, control, and/or feel (particularly around the greens); some designed for faster or slower swing speeds; etc. A host of swing and/or teaching aids also are available on the market that promise to help lower one's golf scores.
Being the sole instrument that sets a golf ball in motion during play, golf clubs also have been the subject of much technological research and advancement in recent years. For example, the market has seen dramatic changes and improvements in putter designs, golf club head designs, shafts, and grips in recent years. Additionally, other technological advancements have been made in an effort to better match the various elements and/or characteristics of the golf club and characteristics of a golf ball to a particular user's swing features or characteristics (e.g., club fitting technology, ball launch angle measurement technology, ball spin rates, etc.).
Given the recent advances, there is a vast array of golf club component parts available to the golfer. For example, club heads are produced by a wide variety of manufacturers in a variety of different models. Moreover, the individual club head models may include multiple variations, such as variations in the loft angle, lie angle, offset features, weighting characteristics (e.g., draw biased club heads, fade biased club heads, neutrally weighted club heads, etc.), etc. Multiple different shafts having differing characteristics, such as stiffness, flex, kickpoint location, etc., also are available. These features give golfers many golf club characteristics and combinations of characteristics from which to choose when selecting a golf club structure that best suits their swing and/or playing style.
In furtherance of improving performance, club designers also have investigated increasing the coefficient of restitution (“COR”) of club heads. The term “COR” also is referred to in the industry as providing a measure of the “trampoline effect” exhibited by a golf club face when it contacts the golf ball. Generally, a COR value provides a measurement of the energy transferred from a first object to a second object upon impact. In golf, COR values may be used to measure the amount of energy transferred from the club to a ball upon impact. COR values are generally expressed numerically from 0 to 1, where 0 would indicate that all energy was lost in the impact, and thus no energy was transferred from the golf club to the ball. In contrast, a COR value of 1 would indicate that 100% of the energy was transferred from the club to the ball on impact. Although other factors may play a role in the overall distance a golf ball travels as a result of a stroke, in general, the higher the COR value for the club face, the larger the amount of energy transferred to the ball (as described above), and thus the higher launch velocity of the ball, which may result in greater distance. The Rules of Golf currently limited a golf club to having a maximum COR value of 0.83.
The “COR” of a golf club face depends on various factors, including, for example, the location on the face where contact with the ball is made. Generally, the COR of a golf club face is highest at a central portion of the club head face, because this portion of the face tends to be the most deformable and thus exhibits the greatest “trampoline effect.” The COR of a club head generally decreases as one moves away from the central area of the face, e.g., due to additional stiffness provided because of bends in the face structure, the sidewalls, and/or other structures located at the sides of the club face.
While advances have been made to increase the coefficient of restitution of golf club heads, additional improvements in this technological area would be a welcome advance in the art.